Memory-type liquid crystals are characterized by the fact that they enter a plurality of optical states and sustain a specific state without application of a voltage (have the capability of a memory). Consequently, when a liquid crystal display device employs the memory-type liquid crystal, the liquid crystal display device can be controlled so that it will sustain a predetermined display without the application of a voltage. A display panel that employs the memory-type liquid crystal such as a ferroelectric liquid crystal so as to utilize the above characteristic of the memory-type liquid crystal is known to be controlled so that scanning electrodes associated with a portion of the surface of the display panel whose display should be modified will be driven but scanning electrodes associated with a portion thereof whose display need not be modified will not be driven (refer to, for example, Patent Document 1).
Normally, the surface of a display panel employing a memory-type liquid crystal is provided with a view plate that covers the perimeter of the surface. An area in the surface associated with the opening of the view plate is referred to as a display area in which display is achieved, and an area in the surface associated with the vicinity of the boundary of the opening formed in the view plate is referred to as a peripheral area. The memory-type liquid crystal has the capability of a memory as mentioned above. However, whichever of a plurality of optical states is sustained with no voltage applied is uncertain. If no driving electrode is associated with the peripheral area because the peripheral area is hardly seen externally, whether the portion of the memory-type liquid crystal coinciding with the peripheral area displays black or white cannot be controlled. The peripheral area coinciding with the uncontrolled portion of the memory-type liquid crystal may be seen from the end of the view plate.
Driving electrodes are therefore associated with the peripheral area, and driving data based on which of the driving electrodes associated with the peripheral area drive the associated portions of the liquid crystal is prepared. Thus, the peripheral area is controlled so that a predetermined color (white or black) will be displayed in the peripheral area (refer to, for example, Patent Document 2).
Moreover, according to a known technique, the driving electrodes associated with the peripheral area are made wider than those associated with the other area in order to cover the peripheral area using a small number of driving electrodes (refer to, for example, Patent Document 3).
Patent Document 1: JP-A-H02-131286 (pp. 11 and 12, FIG. 12)
Patent Document 2: JP-B-2738681 (FIG. 37C)
Patent Document 3: JP-B-2507784 (FIG. 4)
However, if a color to be displayed in the peripheral area is controlled using display data based on which display is achieved in the peripheral area on the display panel employing a memory-type liquid crystal, the display data, based on which display is achieved in the peripheral area, should be preserved independently.
Moreover, a liquid crystal display device has an optically functional film such as a sheet polarizer placed on the upper or lower side of a liquid crystal panel. For a reduction in the cost of a product, the optically functional film should preferably be as small as possible. If the optically functional film required for the liquid crystal display device is placed to cover an unnecessary area, the cost of the display device increases.